SOCS3 expression in cytokine-expressing T cells, T-cell clones, and T_H17 precursor cells. (A) Analysis of median SOCS3 expression in cytokine-positive (dark gray) and cytokine-negative (open) CD4⁺ T cells stimulated with αCD3/CD28 for 36 hours. Bars represent median and SD of 2 replicates. One representative experiment of 3 is shown. *P < .05 (paired t test). (B) Cytokine expression profiles of 4 representative T-cell clones. T-cell clones were restimulated with PMA/ionomycin on day 14 after sorting, and expression of TNF-α, IFN-γ, IL-4, and IL-17 was determined by intracellular cytokine staining. (C) SOCS3 expression analyses of T-cell clones with differential cytokine expression. Each circle represents a T-cell clone with high (●) or low (○) expression for the indicated cytokine. n = 80. **P < .01 (Mann-Whitney U test). (D) Ex vivo analysis of SOCS3 expression in T_H17 (CD161^high) and T_H2 (CRTH2^high) precursor cells by flow cytometry. SOCS3 expression was determined in CD4⁺ T-cell populations that show high or low expression for the respective lineage markers. As a control, SOCS3 expression was also analyzed in CD45RA^high and CD45RA^low CD4⁺ T cells. One representative experiment of 6 is shown for CD161 and CRTH2 and 1 of 3 for CD45RA. Bars represent mean ± SD of 2 replicates. ns indicates not significant. *P < .05 (paired t test).